In conventional blood processing systems (e.g. Patent Documents 1-3), plasma component and blood cell component are separated using a plasma separation membrane or a centrifugal separator and then unnecessary substances are adsorbed and removed by directly bringing the plasma component into contact with an immunoadsorbent, a low-density lipoprotein adsorbent, or the like. In these systems, it is difficult to remove unnecessary substances, such as viruses, and leukocytes simultaneously since the blood cell components such as erythrocytes, Leukocytes, and platelets are collectively separated from the plasma component. Further, in these systems, platelets are activated because these systems use a material having charges. Therefore, it is impossible to recover platelets at a high recovery rate at the same time while removing unnecessary substances and leukocyte.
Patent Document 4 describes a method for purifying blood of a patient with an immunologic disease by simultaneously removing leukocytes and malignant substances such as immunoglobulin from the blood using a material for removing leukocyte. However, the specification describes neither simultaneous removal of leukocytes and viruses nor recovery of platelets to be performed simultaneously with the removal of leukocytes and viruses.
Patent Document 5 describes an apparatus and a method for processing blood, comprising removing a target substance such as a virus from the blood without using an anticoagulant by treating blood with a carrier having a polyamine and an anticoagulant on the surface. However, it is difficult to recover a sufficient amount of platelets, since the surface of the carrier has a large amount of the amine. Also, the degree of removing leukocytes is not sufficient.
As a material for removing a virus, Patent Document 6 describes a material having a cationic compound on the surface. However, the specification does not describe removal of a virus from blood at all. Patent Document 7 describes a material for removing HIV and its related substances, the material having the surface of a weak acidic or weak basic solid substance. This removing material is characterized by having —COOH, —SO3H, or the like on the surface and a surface pH of 2.5-6.9 or 7.4-10.5. The specification describes that a virus cannot be removed when —COOH, —SO3H, or the like on the surface forms a salt. Furthermore, in the method described in Patent Document 7, denaturation or the like of the component protein occurs, which is not favorable for blood, since the pH of blood changes when the blood comes in contact with the removing material. As a problem common to these techniques, there is a risk of blood coagulation due to denaturation of a blood protein when blood comes in contact with a removing material.
(Patent Document 1) Japanese Patent Application Laid-open No. 61-113463
(Patent Document 2) Japanese Patent Publication No. 05-50302
(Patent Document 3) Japanese Patent Publication No. 05-50303
(Patent Document 4) Japanese Patent Publication No. 05-50301
(Patent Document 5) Japanese Patent Application Laid-open No. 11-267199
(Patent Document 6) Japanese Patent Application Laid-open No. 03-123630
(Patent Document 7) Japanese Patent Application Laid-open No. 02-36878